Electronic discharge tube



Oct. 17, 1933. PONTE 1,930,563

ELECTRONIC DISCHARGE TUBE Filed Jan. 23, 1932 MAURICE PONTE INVENTOR BY/2/0ALM,M #60 AT TOR N EYS Patented Oct. 17, 1933 UNITED STATES PATENT OFFICE ELECTRONIC DISCHARGE TUBE France Application January 23, 1932, Serial No. 588,351, and in France February 2, 1931 1 Claim. (01. 250-275) The present invention relates to electronic discharge tubes, and more particularly to such tubes in which the element forming the source of the current which traverses the tube is of such a nature as to vibrate at a natural fre quency. More particularly the invention relates to tubes which are generally designated under the name of multiple electrode tubes and are employed to create electric oscillations or to 0 amplify and detect currents or potentials of various kinds. It is known that apparatus which utilize these electronic discharge tubes are susceptible to shocks or vibrations which produce an instability in the working of the apparatus and also produce noises or a falling out of step of the oscillations, thus rendering the apparatus unusable. These phenomena are particularly noticeable with tubes of which one electrode is formed by a fine and somewhat delicate element such as a filament emitting electrons or, more generally, the ions, which pass through the inter-electrode spaces of the tube. As a matter of fact, the study of noises produced in the apparatus by a valve which comprises a filament of this character shows that they are for the most due to the vibrations of the filament.

The present invention has for its object to prevent these vibrations. Usually the element which vibrates is fixed to supports which transmit the initial impulse so that, for example, the filament is excited by shock and vibrates at a natural frequency in a similar manner to a plucked cord. According to the present invention, means, arranged at a point where an 35 appreciable amplitude of vibration of the element would normally occur, is arranged in contact with the element, as for example, a filament, so as 'to suppress the said vibration.

The means for suppressing the vibration may comprise a member having practically no natural period of vibration or one which is very different from that of the element in question, or alternatively these two conditions may be carried out simultaneously.

The invention will be described with reference to the accompanying drawing in which:

Figures 1 and 2 illustrate, respectively, two methods of carrying the invention into efiect and enable the essential characteristics to be underat a period very different from that of the I strands of the filament. The preferred form of the invention consists in forming the member 4 as a small insulating bar carried by the control electrode 2 which surrounds the filament or by other means.

Other devices than that above described may be employed within the scope of the invention, and are characterized by the fact that they contact with the filament at a point or points which would normally possess an appreciable vibratory amplitude. Another method which has given good results, is represented in Figure 2, and consists in mounting upon the electrode 3 (or any other suitable electrode) a series of inslulating pegs s which contact with the strands of the filament at specially selected points so that the corresponding strands cannot vibrate, such points being indicated at a, b, c.

The invention has been described with special application to the filament of an electronic discharge tube, because it is this element which is the most susceptible of vibration. It is evident that the invention can be applied to any other element, for example, to the helical wire forming a control electrode or to any other element capable of vibrating in the manner described.

I claim:

Electronic discharge tube comprising a system of electrodes including a filament susceptible of vibration, a plate forming the outer electrode of said system, and insulating bars supported from the plate and arranged in contact with the filament, which insulating bars are capable of vibrating at a very different frequency than that of the filament.

MAURICE PONTE. 

